Doctor has a string s consisting of only lowercase letters. Doctor has got the set of all palindromic substrings of a string s, denoted by the set S. Now, he wants to choose two distinct strings a and b from the set S which satisfy that the string a is a substring of the string b. How many different pairs can Doctor choose?
Doctor has a string s consisting of only lowercase letters. Doctor has got the set of all palindromic substrings of a string s, denoted by the set S. Now, he wants to choose two distinct strings a and b from the set S which satisfy that the string a is a substring of the string b. How many different pairs (a, b) can Doctor choose?
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